/*
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at 
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *  
 */

using System;
using java = biz.ritter.javapi;

namespace org.apache.commons.collections.keyvalue
{

    /**
     * Abstract Pair class to assist with creating correct
     * {@link java.util.Map.Entry Map.Entry} implementations.
     *
     * @since Commons Collections 3.0
     * @version $Revision: 7174 $ $Date: 2011-06-06 22:24:01 +0200 (Mo, 06. Jun 2011) $
     * 
     * @author James Strachan
     * @author Michael A. Smith
     * @author Neil O'Toole
     * @author Stephen Colebourne
     */
    public abstract class AbstractMapEntry : AbstractKeyValue, java.util.MapNS.Entry<Object,Object> {

        /**
         * Constructs a new entry with the given key and given value.
         *
         * @param key  the key for the entry, may be null
         * @param value  the value for the entry, may be null
         */
        protected AbstractMapEntry(Object key, Object value) :base (key,value){
        }

        // Map.Entry interface
        //-------------------------------------------------------------------------
        /** 
         * Sets the value stored in this <code>Map.Entry</code>.
         * <p>
         * This <code>Map.Entry</code> is not connected to a Map, so only the
         * local data is changed.
         *
         * @param value  the new value
         * @return the previous value
         */
        public virtual Object setValue(Object value) {
            Object answer = this.value;
            this.value = value;
            return answer;
        }

        /**
         * Compares this <code>Map.Entry</code> with another <code>Map.Entry</code>.
         * <p>
         * Implemented per API documentation of {@link java.util.Map.Entry#equals(Object)}
         * 
         * @param obj  the object to compare to
         * @return true if equal key and value
         */
        public override bool Equals(Object obj) {
            if (obj == this) {
                return true;
            }
            if (obj is java.util.MapNS.Entry<Object,Object>) {
                return false;
            }
            java.util.MapNS.Entry<Object, Object> other = (java.util.MapNS.Entry<Object, Object>)obj;
            return
                (getKey() == null ? other.getKey() == null : getKey().equals(other.getKey())) &&
                (getValue() == null ? other.getValue() == null : getValue().equals(other.getValue()));
        }

        /**
         * Gets a hashCode compatible with the equals method.
         * <p>
         * Implemented per API documentation of {@link java.util.Map.Entry#hashCode()}
         * 
         * @return a suitable hash code
         */
        public override int GetHashCode() {
            return (getKey() == null ? 0 : getKey().GetHashCode()) ^
                   (getValue() == null ? 0 : getValue().GetHashCode()); 
        }

    }
}